Interpretive Summary: Peanut flavor is very important to manufacturers and consumers. Variations in flavor can result in lost revenue and consumer complaints. Identification of the factors that cause peanut off flavors can help in the prevention of those flavors. The compounds responsible for an off flavor identified as fruity fermented were identified in peanuts that developed the off flavor in normal handling practices. Identification of the compounds will assist scientists in development of accurate analytical methods to detect this off flavor.

Technical Abstract:
Published research has indicated that ethyl-2-methylpropanoate, ethyl-2-methybutanaote, ethyl-3-methylbutanoate, hexanoic acid, butanoic acid, and 3-methylbutanoic acid are responsible for fruity fermented (FF) off-flavor and these compounds were identified in samples which were artificially created by curing immature peanuts at a constant high temperature. FF off-flavor related to maturity class and slightly elevated curing temperatures has been examined but volatile compounds associated with flavor developed under those conditions have not been reported. The objective of this study was to characterize the volatile compounds contributing to naturally occurring FF off-flavor to determine the potential for development of methodology to precisely identify peanut lots having FF off flavor.. Volatile compounds of FF and no FF samples were characterized using solid phase microextraction (SPME), gas chromatography-olfactometry (GC-O), and gas-chromatography-mass spectrometry (GC-MS). Aroma extract dilution analysis (AEDA) identified 12 potent aroma active compounds with no consistent differences between the no FF and FF samples. SPME analysis resulted in identification of two of the previously identified esters at very low concentrations. The same two esters were confirmed by SPME at high concentrations in artificially created samples. This study suggests the need for caution in practical application of data from artificially created samples until those compounds are verified in natural samples and indicated that a GC method for detection of natural FF would have limited application because of the extremely low concentrations of the compounds responsible for the off flavor.